Apparatus and buffing element for reconditioning digital recording discs

ABSTRACT

An apparatus ( 46 ) for reconditioning a protective surface ( 30 ) of an optically-read digital recording disc ( 20 ) includes a turntable ( 48 ) configured to receive a center hole ( 24 ) of the disc ( 20 ) and a first motor ( 52 ), coupled to the turntable ( 48 ), for rotating the turntable ( 48 ) and the disc ( 20 ) at a first rotational speed. The apparatus further includes a buffing element ( 50 ) for removing an amount of material from the protective surface ( 30 ) as the turntable rotates the disc ( 20 ) and a second motor ( 54 ), coupled to the buffing element ( 50 ) for rotating the buffing element ( 50 ) at a second rotational speed. A timing element ( 56 ) synchronizes the first and second motors ( 52, 54 ) to substantially simultaneously cease rotation of the turntable ( 48 ) and the buffing element ( 50 ) following removal of an amount of material from the disc ( 20 ). The buffing element ( 50 ) includes a substantially rigid stabilizer plate ( 92 ) and a foam pad ( 88, 90 ) fixedly engaged with a plate surface ( 96 ) of the stabilizer plate ( 92 ). A buffing pad ( 82 ) is in fixed relation with the foam pad ( 88, 90 ). The buffing pad has a first surface ( 102 ) configured to face the foam pad ( 88, 90 ) and a second surface ( 104 ) configured to recondition the protective surface ( 30 ) of the disc ( 20 ).

RELATED PATENTS

[0001] The present invention is a continuation of “Apparatus and BuffingElement for Reconditioning Digital Recording Discs,” Ser. No.09/754,676, filed Jan. 3, 2001, which is incorporated herein byreference.

[0002] The present invention is related to “Method and Apparatus forReconditioning Digital Recording Discs,” by Jason Bauer, U.S. Pat. No.5,954,566, filed Sep. 21, 1999, and incorporated by reference herein.

TECHNICAL FIELD OF THE INVENTION

[0003] The present invention relates generally to optically-read digitalrecording discs. More specifically, the present invention relates toreconditioning the protective surface of digital recording discs.

BACKGROUND OF THE INVENTION

[0004] Optically-read digital recording discs, including compact discs(CDs), digital versatile discs (DVDs), CD-ROMs, recordable CDs (CD-Rs),re-writable CDs (CD-RWs), and the like, are widely used to storedifferent types of information. Digital recording discs may be formattedfor use with audio, video, or computer equipment that reads the datarecorded on the discs. The technology associated with digital discs anddigital playback equipment is well known to those skilled in the art.Basically, digital information is encoded and arranged in spiral datatracks within the disc beneath an optically transparent protectivelayer, or surface, of plastic. A laser beam reads the digitalinformation during playback, and the information is then processed andpresented to the user in the form of sound, visual images, or computerdata.

[0005] The optically transparent protective surface forms the bulk ofthe thickness and weight of the disc. Generally, the protective surfaceprotects the data layer from damage on the play side. In addition, theprotective surface acts as a transparent substrate to support the datalayer of the disc. Damage or surface imperfections located on thetransparent protective surface can interfere with the laser beam beforeit reaches the data layer. Although modern playback devices includeerror correction techniques, this interference can prevent the playerfrom reading the data correctly, or at all, resulting in audibleproblems, even though the data layer itself is undamaged. Due to thehigh cost of digital discs, it is desirable to repair such damaged discsrather than replace them.

[0006] In recent years, the disc reclamation industry has prospered dueto the widespread use and longevity of digital recording discs. However,many used discs cannot be resold because scratches on the protectivesurface render them unplayable or visually unappealing. Consequently, toimprove disc playability and visual appeal, various methods for treatingthe surface of a CD have been developed. However, these prior artmethods suffer from several disadvantages.

[0007] One known process for reconditioning digital recording discsinvolves a motorized apparatus having a buffing surface that abrades theprotective surface in a generally uniform manner across the surface areaof the disc. While this method may effectively repair the protectivesurface of some discs, it can leave fine abrasions on other discs sothat visual appeal is not restored. Moreover, the fine abrasions canfall into alignment with the spiral data track or otherwise affect theoptical tracking quality of the treated disc so that playability is notrestored.

[0008] Another problem with prior art disc reconditioning devices isthat they can leave a ridge-like abrasion pattern. That is, followingreconditioning there is a sudden, or stepwise, change between thethickness of an unconditioned portion of the protective surface and areconditioned portion of the protective surface. A laser beam passingthrough this sharp demarcation may be undesirably bent or scattered sothat the underlying data track or tracks cannot be detected by theplayback equipment.

[0009] The inability to restore playability may be exacerbated whenreconditioning DVDs. DVD playback equipment employs a shorter wavelengthlaser than the other digital playback equipment. This DVD laser iscapable of reading data tracks that are smaller and closer together thanthe data tracks that can be read by the conventional laser in CD playersor CD-ROM drives. Because DVD data tracks are closer together, more ofthem can fit on a disc of the same size. As a result, DVDs can holdabout seven times as much data as an audio CD or a CD-ROM.Unfortunately, fine abrasions remaining on the DVD followingreconditioning can adversely affect the playability of the more closelyspaced DVD data tracks.

[0010] Another result of the different laser in the DVD playbackequipment is that the clear protective surface only needs to be abouthalf as thick for a DVD as it does for an audio CD or CD-ROM. Hence, twoDVDs can be placed back to back, resulting in two play sides and nolabel side, thereby further doubling the data capacity of a DVD. Sincethere is no label side, all manufacturer's identification for the DVD isscreen printed onto the narrow text band just outside of the clampingarea, or stacking ring, of the DVD.

[0011] If a motorized reconditioning apparatus buffs the text band, themanufacturer's identification will be undesirably abraded off leavingthe DVD indistinguishable from other unmarked DVDs. This is highlyundesirable when the DVDs are to be resold. Such a situation is alsoundesirable when the DVDs are used in a rental establishment becausewithout the manufacturer's identification on the text band, the DVDs canbe easily confused with one another. Thus, there is a need for a discreconditioning apparatus that does not damage the text band on thedigital recording disc.

SUMMARY OF THE INVENTION

[0012] Accordingly, it is an advantage of the present invention that anapparatus and buffing element are provided that restore both theplayback quality and the visual appearance of an optically-read digitalrecording disc.

[0013] It is another advantage of the present invention that theapparatus and buffing element effectively recondition the protectivesurface of the disc without causing damage to the text band.

[0014] It is yet another advantage of the present invention that thebuffing element of the present invention imparts a generally uniformabrasion pattern with a gradual transition between unconditioned andreconditioned portions of the disc.

[0015] The above and other advantages of the present invention arecarried out in one form by a buffing element in an apparatus forreconditioning a protective surface of an optically-read digitalrecording disc. The buffing element includes a substantially rigidstabilizer plate having a plate surface and a foam pad fixedly engagedwith the plate surface. A buffing pad is in fixed relation with the foampad, the buffing pad having first and second surfaces on opposing sidesof the buffing pad. The first surface is configured to face the foampad, and the second surface is configured to contact and recondition theprotective surface of the digital recording disc.

[0016] The above and other advantages of the present invention arecarried out in another form by an apparatus for reconditioning aprotective surface of an optically-read digital recording disc. Theapparatus includes a turntable configured to receive a center section ofthe optically-read disc, the center section being located about a centerhole of the optically-read disc. A first motor, coupled to theturntable, rotates the turntable and the optically-read disc at a firstrotational speed. The apparatus further includes a buffing element forremoving an amount of material from the protective surface as theturntable rotates the optically-read disc through at least onerevolution. The buffing element includes a substantially rigidstabilizer plate having a plate surface, a foam pad fixedly engaged withthe plate surface, and a buffing pad in fixed relation with the foampad. The buffing pad has first and second surfaces on opposing sides ofthe buffing pad. The first surface is configured to face the foam pad,and the second surface is configured to recondition the protectivesurface of the digital recording disc. A second motor, coupled to thebuffing element, rotates the buffing element at a second rotationalspeed. A timing element, in communication with each of the first andsecond motors, synchronizes the first and second motors to substantiallysimultaneously cease rotation of the turntable and the buffing elementfollowing removal of the amount of material.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] A more complete understanding of the present invention may bederived by referring to the detailed description and claims whenconsidered in connection with the Figures, wherein like referencenumbers refer to similar items throughout the Figures, and:

[0018]FIG. 1 shows a diagram of an optically-read digital recordingdisc;

[0019]FIG. 2 shows a perspective view of an apparatus for reconditioningprotective surface of an optically-read digital recording disc;

[0020]FIG. 3 shows a side view of a turntable and a buffing element ofthe apparatus of FIG. 2 aligned to recondition a digital recording disc;

[0021]FIG. 4 shows an exploded view of the layers that form the buffingelement of FIG. 3;

[0022]FIG. 5 shows an exploded view of the buffing element beinginstalled on a platen of the apparatus of FIG. 2;

[0023]FIG. 6 shows a top view of the buffing pad adhered to the buffingelement; and

[0024]FIG. 7 shows an expanded side view of a reconditioned portion ofthe digital recording disc.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025]FIG. 1 shows a diagram of an optically-read digital recording disc20. optically-read digital recording disc 20 generally includes a centersection, or clamping area 22, located about a center hole 24 of disc 20.Surrounding clamping area 22 is a narrow text band 26 typically used toidentify the manufacturer. Clamping area 22 and text band 26 to notcontain encoded data. A data layer 28 lies outside of text band 26. Datalayer 28 is arranged in spiral tracks and is covered by a protectivesurface 30. Disc 20 is shown with a portion of protective surface 30removed to show the underlying spiral arranged data layer 28. Anabrasion pattern 32 created in accordance with a disc reconditioningapparatus is shown on protective surface 30 and will be described indetail below.

[0026] When disc 20 is a music compact disc (CD), the first band of datalayer 28 closest to text band 26, called the “lead-in”, contains thetable of contents for the CD. The lead-in tells the CD playbackequipment how to navigate around disc 20. Scratches or other damage inthis area can render disc 20 completely unplayable. In a music CD, thesong tracks of data layer 28 begin just outside the lead-in. Damage todisc 20 in an area of data outside the lead-in usually affects only themusic that is contained in that area. However, with more severe damagethe CD playback equipment can sometimes “lock up” on the damaged area sothat the laser cannot detect later song tracks.

[0027] In general, when disc 20 is undamaged, the laser beam of the discplayback equipment enters disc 20 on the play side, travels throughprotective surface 30, picks up information from data layer 28, andbounces off a reflective coating on the back side of data layer 28. Thereflected laser beam then travels back through protective surface 30,out of disc 20, and into a “detector”. The detector then helps the CDplayer convert the information carried by the laser into sound, video,and/or data.

[0028] An expanded side view 34 of a portion of disc 20 represents anexemplary abraded ridge 36 imparted on disc 20 by a prior art discreconditioning apparatus (not shown). Expanded side view 34 shows anunconditioned portion 38 and a reconditioned portion 40 of disc 20. Asshown in expanded side view 34, a reconditioning process using the priorart reconditioning apparatus imparts abraded ridge 36 betweenunconditioned and reconditioned portions 38 and 40, respectively. Alaser beam 42 entering disc 20 through ridge 36 can be undesirably bentor scattered, as represented by dashed lines 44, so that the underlyingdata layer 28 cannot be accurately detected by the playback equipment.

[0029] The present invention reconditions protective surface 30 of disc20 to remove scratches or other surface imperfections that mightotherwise render disc 20 unplayable or visually unappealing. Inaddition, the present invention reconditions disc 20 outside of textband 26, as represented by abrasion pattern 32, to prevent damage to themanufacturer's identification within text band 26. Furthermore, thepresent invention removes scratches and other surface imperfectionswithout imparting abrasion ridge 36 onto protective surface 30.

[0030] Although disc 20 is generally described as a music CD, it shouldbe understood that optically-read digital recording disc 20 mayalternatively be compact disc read-only memory (CD-ROM), a DigitalVersatile Disc (DVD), recordable CD (CD-R), and Re-writable CDs (CD-RW),and the like. All of the above listed discs are optical discs that areread with a laser in the fashion described above. The primary differencebetween the above listed discs is in how the data is encoded in datalayer 28 and what is done with that data by the player, drive, or otherdevice used to read it.

[0031] Referring to FIGS. 2 and 3, FIG. 2 shows a perspective view of anapparatus 46 for reconditioning protective surface 30 (FIG. 1) ofoptically-read digital recording disc 20 (FIG. 1). FIG. 3 shows a sideview of a turntable 48 and a buffing element 50 aligned to reconditiondigital recording disc 20 in apparatus 34. Apparatus 46 generallyincludes turntable 48 and a turntable motor 52 coupled to turntable 48for rotating turntable 48 at a first rotational speed. Apparatus alsogenerally includes buffing element 50, a buffing element motor 54coupled to buffing element 50 for rotating buffing element 50 at asecond rotational speed, and a timing element 56 coupled to each ofturntable motor 52 and buffing element motor 60.

[0032] Turntable 48 is configured to support and rotate disc 20 during areconditioning process. Turntable 48 is preferably formed from a rigidmaterial such as aluminum. Turntable 48 has an upper surface 57configured to receive clamping area 22 (FIG. 1) located about centerhole 24 (FIG. 1) of disc 20. Desirably, turntable 48 is sized so that itcontacts and covers most of non-data clamping area 22. Upper surface 57includes a spindle 58 configured to receive center hole 24 of disc 20.Spindle 58 functions to centrally position clamping area 22 of disc 20during the reconditioning process.

[0033] In operation, disc 20 is positioned on spindle 58 of turntable 48so that protective surface 30 (FIG. 1) faces turntable 48. Apparatus 46may optionally include a washer 60 that is positioned over disc 20.Washer 60 is configured to limit flexion of disc 20 during thereconditioning process. Washer 60 is preferably formed from a rigid orat least semi-rigid material, such as plastic or aluminum.

[0034] A retainer 62 attaches to spindle 58 and retains washer 60 anddisc 20 on spindle 58 of turntable 48. Retainer 62 may be a threadedscrew which mates with threads on spindle 58. The relatively largesurface area contact between the clamping area 22 and upper surface 57of turntable 48 and the retention capability of retainer 62substantially prevent disc 20 from slipping on turntable 48 when forceis applied to protective surface 30 of disc 20 during rotation. Thoseskilled in the art will recognize that there may be other componentsthat can effectively attach retainer 62 to spindle 58. For example,retainer 62 may include a quick-release locking pin mechanism for rapidengagement or disengagement to spindle 58.

[0035] A platen 64 supports buffing element 50 during the reconditioningprocess. Platen 64 is coupled to buffing element motor 54 via a shaft66. Desirably, platen 64 is sized so that it contacts and supports mostof a non-buffing surface 68 of buffing element 50. In addition, platen64 functions to centrally position and retain buffing element 50 duringthe reconditioning process.

[0036] Buffing element 50 is oriented nearly perpendicular to an axis ofrotation 70 of shaft 66. In addition, axis of rotation 70 of shaft 66 isnearly parallel to an axis of rotation 72 of spindle 58. For example,axis of rotation 70 may be tilted about one degree from axis of rotation72. This nearly parallel alignment of axes 70 and 72 results in a largesurface area of buffing element 50 contacting and buffing protectivesurface 30 during a reconditioning process. Consequently, protectivesurface 30 is buffed in a generally uniform manner across the surfacearea of disc 20.

[0037] Buffing element motor 54 is oriented along axis of rotation 70 bymounting a rear end 74 of buffing element motor 54 to a first end 76 ofa buffing element support 78. Buffing element support 78 may include apivoting adjuster 80 for adjusting buffing element 50 to produce nearlyparallel alignment of axis of rotation 70 of shaft 66 with axis ofrotation of spindle 58. Following alignment, pivoting adjuster 80 islocked into position. Of course, those skilled in the art will recognizethat there are other adjustment schemes which may be employed to producethis nearly parallel alignment. For example, adjustment screws locatedbetween buffing element motor 54 and buffing element 50 may be used toadjust buffing element 50 relative to buffing element motor 54.

[0038] In the preferred embodiment of apparatus 46, protective surface30 of disc 20 is directed in a downward position facing turntable 48,and with only clamping area 22 contacting upper surface 57 of turntable48. Buffing element 50 includes a planar buffing paper, or buffing pad82. Buffing pad 82 is directed in an upward position below disc 20 suchthat a portion of planar buffing pad 82 contacts protective surface 30outside of text band 26 (FIG. 1) as represented by abrasion pattern 32(FIG. 1).

[0039] The orientation of buffing pad 82 below disc 20 allows disc 20 tobe installed and removed from spindle 58 quickly and efficiently. Thoseskilled in the art will recognize that disc 20 and buffing element 50may be oriented in other positions, such as sideways, or upside downfrom the preferred embodiment of apparatus 46, as long as buffingelement 50 continues to face protective surface 30.

[0040] Timing element 56 is set to synchronize turntable and buffingelement motors 52 and 54, respectively, to substantially simultaneouslycease rotation of turntable 48 and buffing element 50. In a system thatdoes not include this synchronization, turntable 48 and disc 20 willcease rotating prior to buffing element 50 due to the difference in therotational speeds between turntable 48 and buffing element 50. This cancause excessive buffing in a limited region of protective surface 30 ofthe non-rotating disc 20 relative to the remaining area of protectivesurface 30. An excessively buffed area creates an unbalanced disc. Anunbalanced disc (which can spin at rotational speeds of up to 500 RPMduring playback) may cause beam focusing problems, vibrations, andsignal distortion during playback.

[0041] In an exemplary embodiment, buffing element motor 54 rotatesbuffing element 50 at a first rotational speed of approximately1000-3400 revolutions per minute (RPM). In contrast, turntable motor 52rotates turntable 48 at a second rotational speed of approximately 20-30RPM. Timing element 56 imparts a time delay on turntable motor 52 sothat turntable 48 and disc 20 continue spinning slightly longer thanbuffing element 50. A time delay of approximately one second causesturntable 48 and buffing element 50 to ramp down and cease rotatingsubstantially simultaneously, thus avoiding the formation of theexcessively buffed region discussed above.

[0042] The rotational speeds of buffing element 50 and turntable 48cause apparatus 46 to remove a substantially uniform amount of materialfrom protective surface 30 in a time efficient manner so that disc 20doesn't get too hot. Excessive heat build-up on disc 20 may damage disc20 so that laser beam 42 (FIG. 1) is unable to focus on data layer 28(FIG. 1). In addition, apparatus may include a cleaning agent dispenser84 located proximate turntable 48.

[0043] Cleaning agent dispenser 84 dispenses a controlled amount of acleaning agent to disc 20 to cool disc 20 and to facilitate the removalof waste material from protective surface 30. The cleaning agent may bewater for rinsing away the waste material produced by the reconditioningprocess. Thus, apparatus 46 may include a collection receptacle 86located proximate turntable 48 for collecting waste material washed offof protective surface 30 by the water. Those skilled in the art willrecognize that other cleaning agents may be used. For example, thecleaning agent may be air blown over protective surface 30 to remove thewaste material.

[0044] The reconditioning process of apparatus 46 causes buffing element50 to contact and buff protective surface 30 along a path. The path isrepresented by abrasion pattern 32 in the view depicted in FIG. 1.Buffing element 50 rotates in a substantially outward radial directionwith respect to turntable 48. Thus, buffing element 50 removes an amountof material from protective surface 30 in an approximately outwardradial direction, represented by abrasion pattern 32. As turntable 48rotates disc 20 through at least one revolution, this pattern isreproduced a multiplicity of times over protective surface 30 of disc20. It should be readily apparent to those skilled in the art thatbuffing element 50 does not etch a scratch corresponding to abrasionpattern 32 into protective surface 30. Rather, abrasion pattern 32merely describes the path in which buffing element 50 moves onprotective surface 30 during the reconditioning process.

[0045] The slight tilt of axis of rotation 70 of shaft 66 relative toaxis of rotation 72 of spindle 58, and the rotation of buffing element50 in the substantially outward radial direction, cause the wastematerial produced by the reconditioning process to be ejected away fromprotective surface 30. The waste material is then washed away by thecleaning agent dispensed by cleaning agent dispenser 84, thus limitingthe undesirable heating of disc 20 while effectively reconditioningprotective surface 30.

[0046]FIG. 4 shows an exploded view of the layers forming buffingelement 50. In a preferred embodiment, buffing element 50 includesbuffing pad 82, a closed cell foam pad 88, a first open cell foam pad90, a substantially rigid stabilizer plate 92, and a second open cellfoam pad 94.

[0047] Substantially rigid stabilizer plate 92 includes a first platesurface 96 and a second plate surface 98. First open cell foam pad 90 iscoupled to first plate surface 96 and second open cell foam pad 94 iscoupled to second plate surface 98. In addition, closed cell foam pad 88is coupled to first open cell foam pad 90. Together, closed cell foampad 88, first open cell foam pad 90, stabilizer plate 92, and secondopen cell foam pad 94 form a platform 100 for affixing buffing pad 82.

[0048] Buffing pad 82 has a first surface 102 and a second surface 104on opposing sides of buffing pad 82. First surface 102 is configured toface closed cell foam pad 88. First surface 102 includes pressuresensitive adhesive so that buffing pad 82 may be removably adhered toclosed cell foam pad 88. Second surface 104 includes abrasive materialand is configured to contact and recondition protective surface 30(FIG. 1) of disc 20 (FIG. 1).

[0049] In a preferred embodiment, closed cell foam pad 88 is a siliconebased closed cell foam pad. A closed cell foam is a type of foam inwhich the chambers in the foam are not interconnected. As such, closedcell foam typically makes good padding and absorbs little water. Thus,closed cell foam pad 88 resists absorbing the cleaning agent provided bycleaning agent dispenser 84 (FIG. 2).

[0050] In addition, a silicone based closed cell foam is advantageousbecause the silicone surface properties provide a firm skin to attachand detach different pressure sensitive adhesives used on first surface102 of buffing pad 82. If other materials are used this ready attachmentand detachment may not occur because the pressure sensitive adhesivesused on first surface 102 will begin to permanently attach themselves tothe other materials. This permanent attachment will shorten the life ofbuffing element 50 undesirably leading to additional cost in the form ofreplacement buffing elements.

[0051] Furthermore, the silicone skin surface can be used in a wetenvironment because it will still allow the attachment of a pressuresensitive backed paper buffing pad 82. This is advantageous whenexchanging a current buffing pad 82 for one that has a coarser or finergrit abrasive since even when wet, the silicone skin surface of closedcell foam pad 88 allows the pressure sensitive adhesive to attachsecurely so that no slippage occurs between buffing pad 82 and closedcell foam pad 88 during operation. Slippage is highly undesirablebecause wrinkles can be created in buffing pad 82 which causes excessivewear of buffing pad 82 in the area of the wrinkles.

[0052] Although closed cell foam pad 88 is described in terms of asilicone based closed cell foam material, it should be understood thatin an alternative embodiment, a non-silicone based closed cell foam padhaving a silicone coated surface may be used. In yet another embodiment,an open cell foam may be used that has been sprayed or coated withsilicone to obtain the properties of water resistance and readyattachment and detachment of buffing pads having pressure sensitiveadhesive backing.

[0053] Typically, silicone based closed cell foam, such as that used toform closed cell foam pad 88, is relatively stiff to compress. Incontrast, open cell foam, such as that used to manufacture first andsecond open cell foam pads 90 and 94, is relatively easy to compressbecause the chambers of open cell foam are interconnected. First andsecond open cell foam pads 90 and 92 may be neoprene or some othermaterial that is soft and readily compressed. Closed cell foam pad 88and first open cell foam pad 90, juxtaposed between closed cell foam pad88 and stabilizer plate 92, function cooperatively to press against andapply pressure to buffing pad 82 in order to produce a visuallyappealing finish on disc 20 (FIG. 1).

[0054] In general, a softer buffing element 50 leads to a better finalfinish. Whereas, a harder buffing element 50 leads to better cut ratefor faster material removal. Thus, although first open cell foam pad 90is described in terms of a soft neoprene foam, and closed cell foam pad88 is described in terms of a relatively stiff silicone foam, it shouldbe understood that other foam materials may be used to obtain thedesired result of final finish or better cut rate.

[0055] Stabilizer plate 92 can be plastic, rubber, fiberglass, metal, orother substantially rigid material with little flex. Stabilizer plate 92creates a firm non-twisting base upon to attach first open cell foam pad90. Stabilizer plate 92 helps reduce wrinkling of buffing pad 82. Inaddition, stabilizer plate 92 substantially prevents distortion ofbuffing element 50 when installing and removing buffing element fromplaten 64 (FIG. 3) to reduce damage and additional wear on buffingelement 50.

[0056]FIG. 5 shows an exploded view of buffing element 50 beinginstalled on platen 64 of apparatus 46 (FIG. 2). Platen 64 includes acenter post 106 and two locator pins 108. Platform 100 and buffing pad82 of buffing element 50 include holes 110 that align with center post106 and locator pins 108 so that buffing element 50 is installed onplaten 64. Locator pins 108 allow accurate location of buffing element50 onto platen 64 and create resistance against twisting force createdby the pressure between buffing element 50 and protective surface 30(FIG. 1) of disc 20 (FIG. 1).

[0057] When buffing element 50 is installed, second open cell foam pad94 is located between platen 64 and stabilizer plate 92. As such, secondopen cell foam pad 94 absorbs vibrations between platen and buffingelement 50 so as to reduce chatter and quiet the operation of apparatus46 (FIG. 2).

[0058] Referring to FIG. 6 in connection with FIG. 5, FIG. 6 shows a topview of buffing pad 82 adhered to closed cell foam pad 88. Closed cellfoam pad 88 exhibits a first diameter 112 and buffing pad 82 exhibits asecond diameter 114. In addition, buffing pad 82 includes radialprojections 116, or scallops, along a perimeter 118 of buffing pad 82.

[0059]FIG. 7 shows an expanded side view of a reconditioned portion ofdisc 20. Radial projections 116 (FIG. 6) of buffing pad 82 (FIG. 6) areconfigured to impart a sloped edge 120 on a border between unconditionedportion 38 and conditioned portion 40 of protective surface 30. That is,radial projections 116 (FIG. 6) function to break up or “feather” thepoint of contact of buffing pad 82 with protective surface 30 (FIG. 1)so as to prevent the development of abraded ridge 36 (FIG. 1) onprotective surface 30. The resulting sloped edge 120 is less likely tocause bending and scattering of laser beam 42 when penetrating thereconditioned disc than that which is caused by abraded ridge 36 (FIG.1). As such, radial projections 116 effectively restore playability ofdisc 20. This is particularly advantageous when reconditioning DVDssince the digital information within data layer 28 (FIG. 1) is muchcloser together than in conventional compact discs.

[0060] In a preferred embodiment, second diameter 114 is less than firstdiameter 112. First diameter 112 is greater than second diameter 114 sothat closed cell foam pad 88 effectively provides support for radialprojections 116 in order to prevent premature wear of the abrasivematerial at radial projections 116.

[0061] Radial projections 116 are shown as being uniform aroundperimeter 118 for clarity. However, it should be understood that radialprojections need not be uniform. Rather, the depth and the shape of thescallop about perimeter 118 can vary as long as the resulting abrasionpattern resembles sloped edge 120.

[0062] In summary, the present invention teaches of an apparatus andbuffing element that restore both the playback quality and the visualappearance of an optically-read digital recording disc. The apparatusincludes a timing element that synchronizes the cessation of rotation ofthe disc and the buffing element to prevent excessive buffing of theprotective coating. In addition, the buffing element is nearly parallelto the protective surface of the disc and positioned so as to uniformlybuff a large surface area of the protective surface during areconditioning process without damage to the text band of the disc.Furthermore, the foam structure of the buffing element provides adequatepressure to the protective surface of the disc to restore playbackquality and the visual appearance to the disc. As further aid in therestoration of playback quality, the scallop pattern of the perimeter ofthe buffing pad imparts a generally uniform abrasion pattern with agradual transition between unconditioned and reconditioned portions ofthe disc. The use of the silicone based closed cell foam and thestabilizer plate results in a cost effective and durable buffingelement.

[0063] Although the preferred embodiments of the invention have beenillustrated and described in detail, it will be readily apparent tothose skilled in the art that various modifications may be made thereinwithout departing from the spirit of the invention or from the scope ofthe appended claims. For example, a single foam pad having theproperties of adequate compression characteristics, resistance to water,and ready adhesion and removal of pressure sensitive adhesives may besubstituted for the closed cell foam pad and the first open cell closedcell foam pad juxtaposed between the stabilizer plate and the buffingpad. In addition, the buffing element may be adapted for use in otherbuffing or polishing applications, such as on the finish of a vehicle,on plastic or fiberglass surfaces, and so forth.

What is claimed is:
 1. In an apparatus for reconditioning a protectivesurface of an optically-read digital recording disc, a buffing elementcomprising: a substantially rigid stabilizer plate having a platesurface, said stabilizer plate exhibiting a plate diameter; a foam padfixedly engaged with said plate surface; and a buffing pad in fixedrelation with said foam pad, said buffing pad having first and secondsurfaces on opposing sides of said buffing pad, said first surface beingconfigured to face said foam pad, said second surface being configuredto contact and recondition said protective surface of said digitalrecording disc, and said buffing pad exhibiting a buffing pad diameter,said plate diameter being substantially equal to or greater than saidbuffing pad diameter.
 2. A buffing element as claimed in claim 1 whereinsaid foam pad is a closed cell foam pad.
 3. A buffing element as claimedin claim 2 further comprising an open cell foam pad juxtaposed betweenand coupled to said closed cell foam pad and said plate surface of saidstabilizer plate.
 4. A buffing element as claimed in claim 2 whereinsaid closed cell foam pad is a silicone based closed cell foam pad.
 5. Abuffing element as claimed in claim 2 wherein said closed cell foam padis a silicone coated closed cell foam pad.
 6. A buffing element asclaimed in claim 1 wherein said foam pad is an open cell foam pad havinga silicone coated surface to which said buffing pad removably adheres.7. A buffing element as claimed in claim 1 wherein: said foam padexhibits a first diameter, and said buffing pad diameter is less thansaid first diameter.
 8. A buffing element as claimed in claim 7 whereinsaid plate diameter of said stabilizer plate is no less than said firstdiameter.
 9. A buffing element as claimed in claim 8 wherein said platediameter is approximately equivalent to said first diameter.
 10. Abuffing element as claimed in claim 1 wherein said first surface of saidbuffing pad includes an adhesive layer that removably adheres to saidfoam pad.
 11. A buffing element as claimed in claim 1 wherein saidapparatus includes a turntable for rotating said buffing element andsaid buffing pad includes radial projections along a perimeter of saidbuffing pad for imparting a sloped edge on a border between anunconditioned portion and a reconditioned portion of said protectivesurface of said disc when said buffing element rotates upon saidturntable.
 12. A buffing element as claimed in claim 1 wherein: saidfoam pad is a first foam pad; said plate surface of said stabilizerplate is a first plate surface; said stabilizer plate further includes asecond plate surface on an opposite side of said stabilizer plate fromsaid first plate surface; and said buffing element further comprises asecond foam pad coupled to said second plate surface of said stabilizerplate.
 13. A buffing element as claimed in claim 12 wherein said secondfoam pad is an open cell foam pad.
 14. A buffing element as claimed inclaim 1 wherein said plate diameter is greater than said buffing paddiameter.
 15. In an apparatus for reconditioning a protective surface ofan optically-read digital recording disc, a buffing element comprising:a substantially rigid stabilizer plate having a plate surface, saidstabilizer plate exhibiting a plate diameter; a foam pad fixedly engagedwith said plate surface, said foam pad exhibiting a foam pad diameter,and said plate diameter being no less than said foam pad diameter; and abuffing pad in fixed relation with said foam pad, said buffing padhaving first and second surfaces on opposing sides of said buffing pad,said first surface being configured to face said foam pad, said secondsurface being configured to contact and recondition said protectivesurface of said digital recording disc, and said buffing pad exhibitinga buffing pad diameter, said plate diameter being greater than saidbuffing pad diameter.
 16. A buffing element as claimed in claim 15wherein said foam pad diameter and said plate diameter are substantiallyequivalent.
 17. A buffing element in an apparatus for reconditioning aprotective surface of an optically-read digital recording disc, saidapparatus including a turntable for rotating said buffing element, saidbuffing element comprising: a substantially rigid stabilizer platehaving a plate surface; an open cell foam pad coupled to said platesurface; a closed cell foam pad coupled to said open cell foam pad; anda buffing pad having first and second surfaces on opposing sides of saidbuffing pad, said first surface being configured to couple to saidclosed cell foam pad, said second surface being configured to contactand recondition said protective surface of said digital recording disc,wherein diameters of each of said stabilizer plate, said open cell foampad, and said closed cell foam pad are greater than a diameter of saidbuffing pad.
 18. A buffing element as claimed in claim 17 wherein saiddiameters of each of said stabilizer plate, said open cell foam pad, andsaid closed cell foam pad are substantially equivalent.